A correspondingly generic drum brake system is known from U.S. Pat. No. 9,175,737 B1, which is incorporated by reference. EP 0 920 390 B1, which is incorporated by reference, has disclosed an electromechanically actuatable drum brake module with a particularly small overall structural size. Here, an outer circumference of a cylindrical actuation unit is inserted through an opening of an anchor plate. A rotatable drive nut is supported via the motor housing on a carrier plate. To shorten the structural length of the actuation unit, it is provided that a rotor of a specially designed electric motor engages radially around the outside of a spindle arrangement and guides said spindle arrangement in a rotationally fixed manner. This type of construction requires a relatively powerfully dimensioned electric motor with a special housing and with a specially adapted carrier plate.
An electromechanically actuatable dual-servo drum brake without cable pull articulation is known from EP 594 233 B1, which is incorporated by reference. Here, an electric motor is arranged on a rear side of an anchor plate. The motor axis is arranged at right angles with respect to an axis of rotation of a brake drum, and drives a threaded spindle which is positioned so as to be rotatable and axially non-displaceable. The threaded spindle is provided, parallel to the motor axis, in the brake drum, and is mounted in a housing. The threaded spindle is in engagement with an element which is mounted in axially displaceable and non-rotatable fashion in the housing, which element acts on a lever mechanism. This type of construction requires not only a relatively powerfully dimensioned electric motor but also further, very specifically designed components, and therefore does not permit easy variation in a mass production context. Hot stoppages are not possible without problems.
U.S. Pat. No. 6,321,884 B1, which is incorporated by reference, defines, in the case of the example of a drum brake system with electric parking brake, an electric method for actuation or release. Here, an electronic control unit serves for electrical modulation during the activation of the parking brake actuator. The electric modulation specifically includes targeted electrical energization and interruption of electrical energization, wherein this modulation must be performed repeatedly if necessary during the ongoing process.
U.S. Pat. No. 8,011,482 B2, which is incorporated by reference, discloses a drum-in-hat drum brake module (DIH) with electric actuation, similar to EP 594 233 B1, the parking brake actuator unit of which comprises a spring element which, in the actuated state, provides a follow-up force in order to provide an additional travel for a tension rod if a brake shoe co-rotation movement occurs.
DE 812 141 C, which is incorporated by reference, discloses a worm gearing.